Chronotype in relation to free and total testosterone in men.

In the current study, we examined the association between eveningness and testosterone levels in men. Specifically, we differentiated between free and total testosterone fractions, with free testosterone being recognized as the most bioavailable form of this hormone. We collected blood samples from 298 men aged 18-44 to assess total and free testosterone. Additionally, we measured sleep timing variables using the Munich Chronotype Questionnaire. The main result of the current study indicated that evening chronotype was associated with higher levels of free testosterone, but was unrelated to total testosterone. Sleep loss was unrelated to the both testosterone fractions. We expanded prior findings by utilizing a more comprehensive testosterone assay what indicated that evening chronotype is primarily associated with the most bioavailable form of testosterone (i.e. free testosterone) in adult men.

Ego-Boosting Hormone: Self-Reported and Blood-Based Testosterone Are Associated With Higher Narcissism.

Grandiose narcissism is defined as increased motivation for status and viewing oneself as entitled and superior to others. We hypothesized that these tendencies might be associated with basal levels of testosterone because testosterone is considered the most social hormone-driving dominance and the motivation to achieve social status. We distinguished between two facets of grandiose narcissism: agentic (i.e., the tendency to self-promotion in order to win others' admiration and social influence) and antagonistic (i.e., a reactive strategy used to restore threatened status). In 283 adult men, we examined the association between these facets of narcissism and blood-tested and self-reported testosterone levels. Agentic narcissism-the default narcissistic strategy-was positively associated with both testosterone indicators. Moreover, self-reported and objectively measured testosterone were positively correlated. These findings extend previous work by showing that the facets of narcissism have distinct hormonal underpinnings.